An electrical machine such as an electrical generator includes a rotor and a stator surrounding the rotor. The stator includes one or more windings. The stator also includes a main portion which terminates at a first end and a second end. Windings in the end extend outwardly from the main portion as outer and inner end windings. These windings are also referred to as top and bottom end windings. As the rotor rotates within the stator, electrical current flows through the windings which results in the generation of electrical power.
The windings are subjected to vibrations and stresses during the operation of the electrical generator. The vibrations in the windings may result in a fault or electrical short circuit that may cause structural deformation in the generator.
As will be appreciated, the natural vibration frequency of end windings in the present electrical generators is typically out of exclusion zone, which is about 120 Hz and is typically twice the operating frequency of the generator which is 50 Hz or 60 Hz. During the operation of the generator, a resulting high vibration and noise in the generator is caused due to possibility of resonance. The high vibrations result in failure of functionality of the components in the generator.
Currently, to increase the natural vibration frequency of the windings a wicking resin is applied on a banding which makes it relatively tight this results in high natural frequency which is greater than 120 Hz. However, after some time the resin starts to break off and the banding becomes loose, which again lowers the natural vibration frequency of the end winding.